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1.
Int J Clin Pract ; 64(4): 442-50, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20456190

RESUMEN

PURPOSE: In the setting of an increasing workload for radiologists, this study focuses on the feasibility of skill mixing in breast imaging in a hospital radiology department. METHODS: Two radiological technologists with more than 10 years of experience in performing mammograms were trained in prereading mammograms to select the cases that require further evaluation by a radiologist. Mammograms of consecutive patients were independently evaluated by the technologists, next to the standard clinical interpretation by the radiologist on duty. Mammographic findings were recorded and a BI-RADS classification was assigned for each breast. Different prereading scenarios were analysed using clinical decision rules. Two different cut-off points of BI-RADS classifications were applied to the data. Analysis was performed for the overall clinical patient population as well as for a subgroup of patients with no immediate indication for further work-up. RESULTS: Mammograms of 1994 patients were evaluated. In total, 93 breast cancers were found in 91 patients (prevalence 4.6%). Sensitivity and specificity in selecting mammographic findings (cut-off point between BI-RADS 1 and BI-RADS 0, 2-5 and the radiologist's diagnosis as reference standard) was 98% and 74% for technologist 1 and 98% and 78% for technologist 2. In distinguishing normal and benign mammograms from those with abnormalities that are probably benign, suspicious or highly suggestive for malignancy (cut-off point BI-RADS 1-2 and BI-RADS 0, 3-5 and pathology results as reference standard), sensitivity decreased to 89% and 91% respectively. Specificity increased to 82% for both technologists. In a subgroup of 1389 patients with no immediate indication for additional imaging with the involvement of a radiologist, technologists obtained a mean sensitivity and specificity of 98% and 77% in detecting mammographic findings, and a mean sensitivity and specificity of 78% and 88% in detecting suspicious abnormalities. CONCLUSIONS: The employment of technologists in prereading mammograms seems to be an effective working strategy in daily clinical practice. However, its position in clinical practice remains indistinct as a continuous availability of radiologists still needs to be guaranteed. Nevertheless, as a substantial proportion of mammograms could be evaluated without the attention of a radiologist, the employment of technologists in prereading mammograms seems a promising new working strategy.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Competencia Clínica/normas , Mamografía/normas , Radiología/normas , Adulto , Anciano , Anciano de 80 o más Años , Reacciones Falso Negativas , Femenino , Humanos , Persona de Mediana Edad , Adulto Joven
2.
Eur J Radiol ; 64(2): 266-72, 2007 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17391885

RESUMEN

PURPOSE: To perform a meta-analysis comparing ultrasonography (US), US guided fine needle aspiration cytology (USgFNAC), computed tomography (CT), and magnetic resonance imaging (MRI) in the detection of lymph node metastases in head and neck cancer. METHODS: MEDLINE, EMBASE and Cochrane databases were searched (January 1990-January 2006) for studies reporting diagnostic performances of US, USgFNAC, CT, and MRI to detect cervical lymph node metastases. Two reviewers screened text and reference lists of potentially eligible articles. Criteria for study inclusion: (1) histopathology was the reference standard, (2) primary tumors and metastases were squamous cell carcinoma and (3) data were available to construct 2 x 2 contingency tables. Meta-analysis of pairs of sensitivity and specificity was performed using bivariate analysis. Summary estimates for diagnostic performance used were sensitivity, specificity, diagnostic odds ratios (DOR) (95% confidence intervals) and summary receiver operating characteristics (SROC) curves. RESULTS: From seventeen articles, 25 data sets could be retrieved. Eleven articles studied one modality: US (n=4); USgFNAC (n=1); CT (n=3); MRI (n=3). Six articles studied two or more modalities: US and CT (n=2); USgFNAC and CT (n=1); CT and MRI (n=1); MRI and MRI-USPIO (Sinerem) (n=2); US, USgFNAC, CT and MRI (n=1). USgFNAC (AUC=0.98) and US (AUC=0.95) showed the highest areas under the curve (AUC). MRI-USPIO (AUC=0.89) and CT (AUC=0.88) had similar results. MRI showed an AUC=0.79. USgFNAC showed the highest DOR (DOR=260) compared to US (DOR=40), MRI-USPIO (DOR=21), CT (DOR=14) and MRI (DOR=7). Conclusion USgFNAC showed to be the most accurate imaging modality to detect cervical lymph node metastases.


Asunto(s)
Biopsia con Aguja Fina/métodos , Neoplasias de Cabeza y Cuello/patología , Metástasis Linfática/diagnóstico , Imagen por Resonancia Magnética , Tomografía Computarizada por Rayos X , Ultrasonografía Intervencional , Área Bajo la Curva , Carcinoma de Células Escamosas/diagnóstico por imagen , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/secundario , Medios de Contraste , Dextranos , Óxido Ferrosoférrico , Humanos , Hierro , Metástasis Linfática/diagnóstico por imagen , Metástasis Linfática/patología , Nanopartículas de Magnetita , Oportunidad Relativa , Óxidos , Curva ROC , Sensibilidad y Especificidad
3.
Ned Tijdschr Geneeskd ; 151(32): 1789-94, 2007 Aug 11.
Artículo en Holandés | MEDLINE | ID: mdl-17822252

RESUMEN

OBJECTIVE: To determine the clinical and economic consequences of replacing duplex ultrasonography (DUS) by contrast-enhanced magnetic resonance angiography (CE-MRA) for the initial diagnostic work-up of patients with peripheral artery disease (PAD). DESIGN: Randomised multicentre study. METHOD: In the period from January 2002 to August 2003, consecutive patients with PAD were randomly assigned to CE-MRA or DUS. The primary outcome measure was the costs. Secondary outcome measures included the confidence with which the specialist could take a therapeutic decision on the basis of the imaging study, the change in disease severity, and the change in quality of life (QOL) assessed during 6 months of follow-up. In addition, all costs of imaging, therapeutic interventions and outpatient visits were calculated. RESULTS: After 6 months of follow-up the data on 352 patients were analysed. Use of CE-MRA reduced the number of additional vascular-imaging procedures by 42% ((69-40)/69) and the specialists felt more confident about their therapeutic decisions. The diagnostic costs of all imaging studies taken together were Euro 167,- higher, on average, in the CE-MRA group (p < 0.001). However, after 6 months of follow-up, no statistically significant differences were found between the two groups with regard to the change in disease severity, the QOL, or the total costs (p > 0.05). CONCLUSION: Based on these findings, a specialist that replaces DUS by CE-MRA will feel more confident about taking a therapeutic decision and will feel less need for additional imaging. However, the diagnostic costs were higher with CE-MRA.

4.
Atherosclerosis ; 187(1): 18-25, 2006 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-16360159

RESUMEN

Incidence of atherosclerosis and atherosclerosis-related complications will increase significantly in the coming decennia. Research identified many serum and plasma markers that are associated with cardiovascular disease. However, little is known about the prognostic value of these markers to identify patients at risk for future cardiovascular events. Therefore, we aimed to investigate the prognostic value of three of these markers (soluble CD40 ligand (sCD40L), interleukin-6 (IL-6) and oxidized low-density lipoprotein (oxLDL)) with respect to coronary vascular disease and stroke. For this reason the Medline database was searched for the period January 1999-January 2005. To be selected in our study, concentration of the marker had to be determined at baseline, follow-up period had to be longer than 3 months and an estimate of relative risk had to be available. Based on these criteria, 4 studies for sCD40L, 10 for IL-6 and 2 for oxLDL were selected. Relative risk estimates adjusted for potential confounders varied between 1.9 and 2.8 for sCD40L, between 1.1 and 3.1 for IL-6 and between 1.9 and 3.2 for oxLDL. In conclusion, this systematic review shows that sCD40L, IL-6 and oxLDL are associated with an increased relative risk of developing cardiovascular disease.


Asunto(s)
Proteína C-Reactiva/fisiología , Ligando de CD40/biosíntesis , Enfermedad Coronaria/diagnóstico , Vasos Coronarios/patología , Fibrinógeno/fisiología , Interleucina-6/sangre , Lipoproteínas LDL/metabolismo , Enfermedades Vasculares/diagnóstico , Proteína C-Reactiva/biosíntesis , Enfermedad Coronaria/sangre , Bases de Datos Bibliográficas , Fibrinógeno/biosíntesis , Humanos , Modelos Estadísticos , Pronóstico , Factores de Riesgo , Enfermedades Vasculares/sangre
5.
AJNR Am J Neuroradiol ; 27(7): 1573-5, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16908583

RESUMEN

SUMMARY: Spinal cord arteries and veins are difficult to visualize and distinguish by MR angiographic techniques because of their small sizes, similar spatial course, and close vascular anatomy. Contrast-enhanced MR angiography was demonstrated to dynamically resolve the Adamkiewicz artery from the anterior radiculomedullary vein in the thoracolumbar spinal cord. The location of the Adamkiewicz artery and the anterior radiculomedullary vein could be validated in the postmortem specimen of a thoracoabdominal aortic aneurysm patient.


Asunto(s)
Angiografía por Resonancia Magnética , Médula Espinal/irrigación sanguínea , Anciano , Aneurisma de la Aorta Abdominal/cirugía , Aneurisma de la Aorta Torácica/cirugía , Arterias/patología , Medios de Contraste , Resultado Fatal , Femenino , Humanos , Aumento de la Imagen , Complicaciones Posoperatorias
6.
Circulation ; 107(19): 2453-8, 2003 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-12719280

RESUMEN

BACKGROUND: One of the features of high-risk atherosclerotic plaques is a preponderance of macrophages. Experimental studies with hyperlipidemic rabbits have shown that ultrasmall superparamagnetic particles of iron oxide (USPIOs) accumulate in plaques with a high macrophage content and that this induces magnetic resonance (MR) signal changes. The purpose of our study was to investigate whether USPIO-enhanced MRI can also be used for in vivo detection of macrophages in human plaques. METHODS AND RESULTS: MRI was performed on 11 symptomatic patients scheduled for carotid endarterectomy before and 24 (n=11) and 72 (n=5) hours after administration of USPIOs (Sinerem) at a dose of 2.6 mg Fe/kg. Histological and electron microscopical analyses of the plaques showed USPIOs primarily in macrophages within the plaques in 10 of 11 patients. Histological analysis showed USPIOs in 27 of 36 (75%) of the ruptured and rupture-prone lesions and 1 of 14 (7%) of the stable lesions. Of the patients with USPIO uptake, signal changes in the post-USPIO MRI were observed by 2 observers in the vessel wall in 67 of 123 (54%) and 19 of 55 (35%) quadrants of the T2*-weighted MR images acquired after 24 and 72 hours, respectively. For those quadrants with changes, there was a significant signal decrease of 24% (95% CI, 33% to 15%) in regions of interest in the images acquired after 24 hours, whereas no significant signal change was found after 72 hours. CONCLUSIONS: Accumulation of USPIOs in macrophages in predominantly ruptured and rupture-prone human atherosclerotic lesions caused signal decreases in the in vivo MR images.


Asunto(s)
Enfermedades de las Arterias Carótidas/diagnóstico , Enfermedades de las Arterias Carótidas/metabolismo , Compuestos Férricos/metabolismo , Imagen por Resonancia Magnética , Arterias Carótidas/patología , Arterias Carótidas/ultraestructura , Enfermedades de las Arterias Carótidas/clasificación , Enfermedades de las Arterias Carótidas/complicaciones , Dextranos , Espectroscopía de Resonancia por Spin del Electrón , Endotelio Vascular/patología , Endotelio Vascular/ultraestructura , Estudios de Factibilidad , Femenino , Óxido Ferrosoférrico , Humanos , Hierro , Ataque Isquémico Transitorio/etiología , Macrófagos/metabolismo , Imagen por Resonancia Magnética/métodos , Nanopartículas de Magnetita , Masculino , Microscopía Electrónica , Persona de Mediana Edad , Músculo Liso Vascular/patología , Músculo Liso Vascular/ultraestructura , Óxidos , Tamaño de la Partícula , Valor Predictivo de las Pruebas
8.
Semin Ultrasound CT MR ; 26(4): 259-68, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16152740

RESUMEN

The aim of the present study was to conduct a meta-analysis of English literature on the accuracy of preoperative imaging in predicting the two most important risk factors for local recurrence in rectal cancer, the circumferential resection margin (CRM) and the nodal status (N-status). Articles published between 1985 and August 2004 that report on the diagnostic accuracy of endoluminal ultrasound (EUS), computed tomography (CT), or magnetic resonance imaging (MRI) in the evaluation of lymph node involvement were included. A similar search was done for the assessment of the circumferential resection margin in rectal cancer in the period from January 1985 till January 2005. The inclusion criteria were as follows: (1) more than 20 patients with histologically proven rectal cancer were included, (2) histology was used as the gold standard, and (3) results were given in a 2 x 2 contingency table or this table could otherwise be extracted from the article by two independent readers. Based on the results summary receiver operating characteristic (ROC) curves were constructed. Only 7 articles matching inclusion criteria were found concerning the CRM. The meta-analysis shows that MRI is rather accurate in diagnosing a close or involved CRM. For nodal status 84 articles could be included. The diagnostic odds ratio of EUS is estimated at 8.83. For MRI and CT, the diagnostic odds ratio are 6.53 and 5.86, respectively. The results show that EUS is slightly, but not significantly, better than MRI or CT for identification of nodal disease. There is no significant difference between the different modalities with respect to staging nodal status. At present, MRI is the only modality that predicts the circumferential resection margin with good accuracy, making it a good tool to identify high and low risk patients. Predicting the N-status remains a problem for the radiologist for every modality, although considering the new developments in MR imaging, this may change in the near future.


Asunto(s)
Diagnóstico por Imagen , Neoplasias del Recto/diagnóstico , Humanos , Metástasis Linfática , Recurrencia Local de Neoplasia , Estadificación de Neoplasias , Valor Predictivo de las Pruebas , Curva ROC , Neoplasias del Recto/patología , Neoplasias del Recto/cirugía , Factores de Riesgo
9.
J Clin Endocrinol Metab ; 88(4): 1610-6, 2003 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-12679446

RESUMEN

The present study investigated the influences of a 2-wk training program on intramyocellular lipid (IMCL) content, IMCL decrease during exercise, fat oxidation, and insulin sensitivity. Nine untrained men (age, 23.3 +/- 3.2 yr; body mass index, 22.6 +/- 2.6 kg/m(2); maximal power output, 3.8 +/- 0.6 W/kg body weight) trained for 2 wk. Before and after training, subjects cycled for 3 h while substrate oxidation was measured. IMCL content in the vastus lateralis muscle was determined before and after cycling by proton magnetic resonance spectroscopy. Before and after training, insulin sensitivity was assessed by an insulin tolerance test. The training period resulted in a significant increase in IMCL content by 42 +/- 14%. IMCL content decreased significantly during cycling. However, 2 wk of training were not sufficient to achieve increases in fat oxidation and/or use of IMCL during exercise. All markers used to test insulin sensitivity point toward improved insulin sensitivity, albeit not significant. We conclude that the increase in IMCL content is a very early response to training, preceding significant changes in insulin sensitivity. The results suggest that the presence of triglycerides alone does not necessarily have detrimental effects on insulin sensitivity. We confirm earlier reports that IMCL contributes to the energy used during prolonged submaximal exercise.


Asunto(s)
Ejercicio Físico , Lípidos/análisis , Músculo Esquelético/química , Tejido Adiposo , Adulto , Ciclismo , Composición Corporal , Índice de Masa Corporal , Metabolismo Energético , Glicerol/sangre , Humanos , Insulina/farmacología , Espectroscopía de Resonancia Magnética , Masculino , Músculo Esquelético/ultraestructura , Oxidación-Reducción , Resistencia Física , Factores de Tiempo
10.
Eur J Cancer ; 38(8): 1044-50, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-12008191

RESUMEN

The aim of this review was to summarise the diagnostic performance of ultrasonography as an adjunct to mammography in the detection of breast cancer and to identify clinical indications. A systematic review was performed of all publications in MEDLINE and EMBASE between 1990 and 2000 on the role of ultrasonography as an adjunct to mammography. 22 studies were included, showing a large variety of indications for ultrasonography and variations in the diagnostic performance of mammography and ultrasonography. There were six studies comparing a combined diagnosis of mammography and ultrasonography together with mammography alone, of which three studies had an increased sensitivity at the cost of a lower specificity. The methods of selecting the study population and interpretation of ultrasonography significantly influenced the diagnostic performance of mammography and ultrasonography relative to each other (P=0.003, P=0.03, respectively). Based on the studies reviewed, little evidence-based support was found to confirm the well recognised value of ultrasonography as an adjunct to mammography in the detection of breast cancer in clinical practice. Furthermore, no clinical indications for additional ultrasonography could be defined. The heterogeneity in the diagnostic performance in these studies may be explained by the methods of patient selection and ultrasonography interpretation, as well as by their poor quality.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Mamografía/métodos , Ultrasonografía Mamaria/métodos , Femenino , Humanos , Sensibilidad y Especificidad
11.
Eur J Cancer ; 40(8): 1262-8, 2004 May.
Artículo en Inglés | MEDLINE | ID: mdl-15110892

RESUMEN

The purpose of this study was to evaluate the effects of anginex on tumour angiogenesis assessed by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) on a clinical 1.5 Tesla MR system and with the clinically available contrast agent gadopentetate dimeglumine. C57BL/6 mice carrying B16F10 melanomas were treated with anginex, TNP-470 or saline. Tumour growth curves and microvessel density (MVD) were recorded to establish the effects of treatment. DCE-MRI was performed on day 16 after tumour inoculation, and the endothelial transfer coefficients of the microvessel permeability surface-area product (K(PS)) were calculated using a two-compartment model. Both anginex and TNP-470 resulted in smaller tumour volumes (P<0.0001) and lower MVD (P <0.05) compared to saline. Treatment with anginex resulted in a 64% reduction (P<0.01) of tumour K(PS) and TNP-470 resulted in a 44% reduction (P=0.17), compared to saline. DCE-MRI with a clinically available, small-molecular contrast agent can therefore be used to evaluate the angiostatic effects of anginex and TNP-470 on tumour angiogenesis.


Asunto(s)
Inhibidores de la Angiogénesis/uso terapéutico , Melanoma/irrigación sanguínea , Neovascularización Patológica/prevención & control , Animales , Medios de Contraste , Gadolinio DTPA , Imagen por Resonancia Magnética/métodos , Melanoma/tratamiento farmacológico , Ratones , Ratones Endogámicos C57BL , Neovascularización Patológica/diagnóstico , Péptidos , Proteínas
12.
J Hum Hypertens ; 16(7): 501-7, 2002 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12080435

RESUMEN

The aim of this study was to evaluate the accuracy of duplex ultrasound for the diagnosis of renovascular disease in a cohort of hypertensive patients. In 78 patients suspected of renovascular hypertension on clinical grounds duplex ultrasound examination of the renal arteries was performed. Renal angiography was used as the standard of reference. Duplex ultrasound was inconclusive in 11 kidneys (7%). None of the supernumerary renal arteries was detected with duplex ultrasound. The overall prevalence of significant renovascular disease (> or =50% stenosis) was 20%. Based on the combination of parameters at thresholds commonly applied in current literature: ie PSV(max) >180 cm/sec and RAR >3.5 the overall sensitivity of duplex ultrasound for detection of haemodynamically significant renovascular disease was 50.0% with a specificity of 91.3% (PPV: 87.9%; NPV: 59.1). Lowering the thresholds for both parameters improved the test results at the cost of a significant increase of false positive examinations. In a population of hypertensive patients clinically suspected of renovascular hypertension, only limited results for duplex ultrasound could be acquired in the detection of renovascular disease. This result, in combination with the wide range of sensitivities and specificities published in international literature and the relatively large number of incomplete examinations does not support the general application of duplex ultrasound as a screening procedure for detection and assessment of renovascular disease.


Asunto(s)
Hipertensión/diagnóstico por imagen , Hipertensión/etiología , Obstrucción de la Arteria Renal/complicaciones , Obstrucción de la Arteria Renal/diagnóstico por imagen , Ultrasonografía Doppler Dúplex , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Radiografía , Arteria Renal/diagnóstico por imagen , Arteria Renal/fisiopatología , Circulación Renal/fisiología , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad
13.
Breast ; 13(6): 476-82, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15563854

RESUMEN

BACKGROUND: The achievement of tumour-free margins on excision of nonpalpable breast lesions that have aroused only an intermediate or low level of suspicion before surgery and do turn out to be malignant is a challenge for the surgeon. The purpose of this study was to determine factors that influence the probability of obtaining tumour-free margins after needle-localised excision of a nonpalpable breast carcinoma. METHOD: During a 10-year period all needle-localised breast biopsies (NLBB) carried out in the Department of Surgery were retrospectively analysed. Possible influential factors considered included: age of the patient, year of NLBB, appearance of the lesion on imaging, preoperative diagnostic index, method of localisation, surgeon's level of experience, specimen size and radiology of the specimen, and all these were analysed in a multivariate logistic regression analysis. RESULTS: In all, 400 needle-localised breast biopsies had been performed. Excision with tumour-free margins was more often achieved, and the final intervention less often took the form of a mastectomy, when the lesion was classified preoperatively as malignant (P = 0.02). CONCLUSION: The outcome of treatment of a needle-localised breast cancer excision is better when the breast lesion is known to be malignant before surgery.


Asunto(s)
Neoplasias de la Mama/patología , Adulto , Anciano , Anciano de 80 o más Años , Biopsia con Aguja , Neoplasias de la Mama/cirugía , Carcinoma in Situ/patología , Femenino , Humanos , Mastectomía Segmentaria , Persona de Mediana Edad , Análisis de Regresión , Estudios Retrospectivos , Sensibilidad y Especificidad
14.
J Nephrol ; 16(6): 807-12, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-14736007

RESUMEN

BACKGROUND: Atherosclerotic renal artery stenosis (ARAS) is associated with progressive loss of renal function and is one of the most important causes of renal failure in the elderly. Current treatment includes restoration of the renal arterial lumen by endovascular stent placement. However, this treatment only affects damage caused by ARAS due to the stenosis and ensuing post-stenotic ischemia. ARAS patients have severe general vascular disease. Atherosclerosis and hypertension can also damage the kidney parenchyma causing renal failure. Medical treatment focuses on the latter. Lipid-lowering drugs (statins) could reduce renal failure progression and could reduce the overall high cardiovascular risk. The additional effect on preserving renal function of stent placement as compared to medical therapy alone is unknown. Therefore, the STAR-study aims to compare the effects of renal artery stent placement together with medication vs. medication alone on renal function in ARAS patients. METHOD: Patients with an ARAS of > or = 50% and renal failure (creatinine (Cr) clearance < 80 mL/min/1.73 m2) are randomly assigned to stent placement with medication or to medication alone. Medication consists of statins, anti-hypertensive drugs and antiplatelet therapy. Patients are followed for 2 yrs with extended follow-up to 5 yrs. The primary outcome of this study is a reduction in Cr clearance > 20% compared to baseline. This trial will include 140 patients.


Asunto(s)
Antihipertensivos/uso terapéutico , Arteriosclerosis/terapia , Ácidos Heptanoicos/uso terapéutico , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Pirroles/uso terapéutico , Obstrucción de la Arteria Renal/terapia , Arteria Renal , Stents , Angioplastia de Balón , Arteriosclerosis/complicaciones , Arteriosclerosis/fisiopatología , Atorvastatina , Terapia Combinada , Progresión de la Enfermedad , Humanos , Riñón/fisiopatología , Obstrucción de la Arteria Renal/etiología , Obstrucción de la Arteria Renal/fisiopatología , Proyectos de Investigación
15.
Br J Radiol ; 76(905): 328-31, 2003 May.
Artículo en Inglés | MEDLINE | ID: mdl-12763948

RESUMEN

The purpose of this study was to determine the interexamination agreement of ultrasound of the breasts. This includes the complete process of performing whole breast ultrasound and interpreting the dynamic scanning and the static images by one person. In a prospective study, 58 patients with a clinical indication for mammography underwent an ultrasound examination of both breasts by three independent sonographers. The sonographers had full knowledge of the physical and mammographic findings. Histology and 12 month follow-up were used as the reference standard. Interobserver variability for both mammography and breast ultrasound was measured using linearly weighted kappa statistics. Receiver operator characteristic curves were constructed to compare the diagnostic performance of the observers. The interexamination agreement for the score of the probability of malignancy after mammography was substantial (kappas ranged from 0.63 to 0.65). The interexamination agreement for the final score of the probability of malignancy after mammography and ultrasound examination was slightly better (kappas ranged from 0.72 to 0.75). The area under the receiver operating characteristic curves after mammography and ultrasound examination ranged from 0.97 to 0.98. Ultrasound examination of the whole breast shows a substantial interexamination agreement. Ultrasound examination of the breast adds consistency to mammography and physical examination.


Asunto(s)
Enfermedades de la Mama/diagnóstico por imagen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias de la Mama/diagnóstico por imagen , Femenino , Humanos , Mamografía , Persona de Mediana Edad , Variaciones Dependientes del Observador , Estudios Prospectivos , Ultrasonografía
16.
Br J Radiol ; 76(909): 625-30, 2003 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-14500277

RESUMEN

Patient radiation dose in angiography of the renal arteries was assessed and optimized after installing new radiological equipment. In three separate studies (n=50, 25 and 20) patient exposure was monitored in detail. For the first study default factory settings were used, for the second the number of digital subtraction angiography (DSA) images was halved and the X-ray beam filtering during fluoroscopy was increased, and for the third study filtering during DSA was increased as well. Standard projections were derived and used in Monte Carlo simulations to derive dose conversion coefficients to calculate effective dose from the dose-area product (DAP). Dose conversion coefficients were also calculated for CT angiography (CTA). Using default factory settings on the new angiography system, DAP, number of images and effective dose were much higher than on the replaced unit. For the studies given above, DAP was reduced from 144 Gy cm(2) to 65 Gy cm(2) to 32 Gy cm(2), and effective dose from 22 mSv to 11 mSv to 9.1 mSv, respectively. Effective dose due to CTA was 5.2 mSv. It is concluded that modern angiography systems, resulting in high customer satisfaction, may readily cause much higher patient exposure than older systems. These doses may also be much higher than necessary. Optimization before putting such systems into use is absolutely essential. Internationally accepted recommendations for image quality and technique factors in angiography would be of great help.


Asunto(s)
Angiografía/instrumentación , Dosis de Radiación , Arteria Renal/diagnóstico por imagen , Tomografía Computarizada por Rayos X/instrumentación , Adolescente , Adulto , Anciano , Angiografía/métodos , Presión Sanguínea/fisiología , Femenino , Fluoroscopía , Humanos , Hipertensión/diagnóstico por imagen , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad , Método de Montecarlo , Tomografía Computarizada por Rayos X/métodos
17.
Comput Methods Programs Biomed ; 67(3): 169-76, 2002 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11853942

RESUMEN

With the high resolution of dynamic magnetic resonance imaging (MRI) scans it is possible to measure cortical renograms directly, but due to partial volume effects this is impossible for medullary renograms. With weighted subtraction of the cortical renogram from a mixed renogram it becomes possible to extract the medullary renogram. For this subtraction the fraction of cortical tissue, present in the region of interest in which the mixed renogram is determined, has to be calculated. We have evaluated two algorithms for calculation of the cortical fraction. Both algorithms use the fact that during an interval after the start of the cortical enhancement no medullary enhancement occurs. One algorithm calculates the ratio between the slopes of both enhancement curves. The other is based on minimising the medullary signal values using a least squares error (LSE) method. Using a computer model of the renograms and measurements on real patients we analysed the accuracy of both methods and determined the best parameters for each.


Asunto(s)
Algoritmos , Corteza Renal/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Humanos , Trasplante de Riñón , Radiografía
18.
AJNR Am J Neuroradiol ; 32(5): 950-4, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21330389

RESUMEN

BACKGROUND AND PURPOSE: There is a need for improved risk stratification of patients with TIA/stroke and carotid atherosclerosis. The purpose of this study was to prospectively investigate the potential of integrated (18)F-FDG PET/MDCT in identifying vulnerable carotid plaques. MATERIALS AND METHODS: Fifty patients with TIA/stroke with an ipsilateral carotid plaque causing <70% stenosis and a plaque on the contralateral asymptomatic side underwent integrated (18)F-FDG PET/MDCT within 36.1 ± 20.0 days (range, 9-95 days) of the last symptoms. Carotid plaque (18)F-FDG uptake was measured as both the mean and maximum blood-normalized SUV, known as the TBR. Using MDCT, we assessed volumes of vessel wall and individual plaque components. RESULTS: Mean TBR was only significantly larger in the ipsilateral plaques of patients who were imaged within 38 days (1.24 ± 0.04 [SE] versus 1.17 ± 0.05, P = .014). This also accounted for maximum TBR (1.53 ± 0.06 versus 1.42 ± 0.06, P = .015). MDCT-assessed vessel wall and LRNC volumes were larger in ipsilateral plaques of all patients (982.3 ± 121.3 versus 811.3 ± 106.6 mm(3), P = .016; 164.7 ± 26.1 versus 134.3 ± 35.2 mm(3), P = .026, respectively). CONCLUSIONS: In the present study, (18)F-FDG PET only detected significant differences between ipsilateral and contralateral asymptomatic plaques in patients with TIA/stroke who were imaged within 38 days, whereas MDCT detected larger vessel wall and LRNC volumes, regardless of time after symptoms. In view of the substantial overlap in measurements of both sides, it remains to be determined whether the differences we found will be clinically meaningful.


Asunto(s)
Estenosis Carotídea/complicaciones , Estenosis Carotídea/diagnóstico , Fluorodesoxiglucosa F18 , Tomografía de Emisión de Positrones/métodos , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/etiología , Tomografía Computarizada por Rayos X/métodos , Anciano , Estudios de Factibilidad , Femenino , Humanos , Masculino , Radiofármacos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Técnica de Sustracción
19.
Qual Saf Health Care ; 19(6): 503-8, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20551187

RESUMEN

OBJECTIVE: To assess the adherence to a guideline for additional breast ultrasonography in a cross-sectional survey among hospitals in The Netherlands. Furthermore, consequences of current practice non-adherence for the patient outcome of diagnostic breast imaging were studied. METHODS: Current practice was compared with a guideline made up of three recommendations for the use of ultrasonography after mammography and three recommendations for not using ultrasonography. All patients referred for mammography to the radiology departments of the participating hospitals during 2 months in 2004 were eligible for the study. No data on the gold standard for breast cancer were analysed, but clinical consequences were estimated by using a probability model based on the data of a former prospective clinical study. RESULTS: In total, 17 of the 66 hospitals approached were participating in the study. Of the 13,694 patients assessed for eligibility, 6457 were included. High adherence rates (81-97%, mean 94%) were observed for the recommendations, which indicate additional ultrasonography, whereas lower adherence rates (68-94%, mean 83%) were seen for the recommendations which do not advise additional ultrasonography. Overall, in all included hospitals, non-adherence would result in 27.2 false-positive and 1.1 false-negative imaging results. CONCLUSION: Current daily practice of diagnostic breast imaging in the hospitals in this survey corresponds to a great extent to the guideline proposed. Non-adherence in current practice results in a relatively small number of false-positive and false-negative imaging results.


Asunto(s)
Adhesión a Directriz , Evaluación de Resultado en la Atención de Salud , Derivación y Consulta , Ultrasonografía Mamaria , Adulto , Neoplasias de la Mama/diagnóstico por imagen , Estudios Transversales , Reacciones Falso Negativas , Reacciones Falso Positivas , Femenino , Humanos , Modelos Estadísticos , Países Bajos , Estudios Prospectivos , Servicio de Radiología en Hospital
20.
Int J Vasc Med ; 2010: 726207, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-21188207

RESUMEN

We evaluated leukocyte counts and levels of CRP, fibrinogen, MPO, and PAPP-A in patients with stable and unstable angina pectoris, acute myocardial infarction, and healthy controls. All biomarkers were analyzed again after 6 months. Leukocyte counts and concentrations of fibrinogen, CRP, MPO, and PAPP-A were significantly increased in patients with acute myocardial infarction. Leukocyte counts and concentrations of MPO were significantly increased in patients with unstable angina pectoris compared with controls. After 6 months, leukocyte counts and MPO concentrations were still increased in patients with acute myocardial infarction when compared to controls. Discriminant analysis showed that leukocyte counts, MPO, and PAPP-A concentrations classified study group designation for acute coronary events correctly in 83% of the cases. In conclusion, combined assessment of leukocyte counts, MPO, and PAPP-A was able to correctly classify acute coronary events, suggesting that this could be a promising panel for a multibiomarker approach to assess cardiovascular risk.

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